[Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function

[Peter Maydell]

Currently the vmstate subsection handling code treats a subsection
with no 'needed' function pointer as if it were the subsection
list terminator, so the subsection is never transferred and nor
is any subsection following it in the list.

Handle NULL 'needed' function pointers in subsections in the same
way that we do for top level VMStateDescription structures:
treat the subsection as always being needed.

This doesn't change behaviour for the current set of devices
in the tree, because all subsections declare a 'needed' function.

Signed-off-by: Peter Maydell <address@hidden>
---
NB: last para in the commit message is only true once the
"Arm migration fixes for 3.0" patchset has been committed.
We could optionally drop some of the "use a dummy needed fn"
changes once this is in...

I thought I'd sent this out a few days back, but apparently not,
since it's not on-list...

 migration/vmstate.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/migration/vmstate.c b/migration/vmstate.c
index 6b9079bb51e..0bc240a3175 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -418,7 +418,7 @@ int vmstate_save_state_v(QEMUFile *f, const 
VMStateDescription *vmsd,
 static const VMStateDescription *
 vmstate_get_subsection(const VMStateDescription **sub, char *idstr)
 {
-    while (sub && *sub && (*sub)->needed) {
+    while (sub && *sub) {
         if (strcmp(idstr, (*sub)->name) == 0) {
             return *sub;
         }
@@ -486,8 +486,8 @@ static int vmstate_subsection_save(QEMUFile *f, const 
VMStateDescription *vmsd,
     int ret = 0;
 
     trace_vmstate_subsection_save_top(vmsd->name);
-    while (sub && *sub && (*sub)->needed) {
-        if ((*sub)->needed(opaque)) {
+    while (sub && *sub) {
+        if (vmstate_save_needed(*sub, opaque)) {
             const VMStateDescription *vmsdsub = *sub;
             uint8_t len;
 
-- 
2.17.1